Pretty self explanatory. A guy setup a pokemon game, red I believe, to twitch. People would type in commands into chat and what they typed would take place in the game, with a bit of a delay of course. Now, imagine... 300k people all spamming a chat room trying to get the game to do what needs to be done. At least 70k of that is trolls. And the rest are just punching in random ****. That's basically twitch plays pokemon.

TwitchPlaysPokemon [TPP] is a social experiment, it is a stream of the Gameboy version of Pokemon Red (151 romhack) running on an emulator. An IRC bot translates buttons said in chat into keypresses (simulated in software, no fancy typist robots).

The game allows you to "use" the fossil, which provokes the long, slow, process of Oak stating the famous line "now is not the time to use that!".
The players would, for hours on end, try to "use" the fossil, essentially worshiping it, when they were lost, or most particularly, arguing about which way to go. This was a way to stall until an agreement was made, essentially, a filibuster.
Anyway, the Helix fossil eventually was revived and became Omanyte-Omastar.

It began as a joke when people were constantly going to their inventory and clicking on the helix fossil by accident during Pokemon battles. It looked like they were worshiping it every time. Eventually people decided to create a "religion" out of it.